First, your immune system becomes low leading to flu and depression. Our gut bacteria affects our mood as reported in my blog, clubalthea .

Our nose has so many bacteria fighting mucus and cilia.

Nasal epithelial cilia continually transport mucus with ensnared particulate matter … Lysozymes acts as antimicrobial properties of human nasal cavity.

It also has including lactoferrin, mucus glycoproteins, secretory leukoprotease inhibitor (SLPI), uric acid, peroxidase, aminopeptidase, immunoglobulins, and neutral endopeptidase.

Pathological alterations in antimicrobial properties of airway secretions may contribute to epithelial colonization by bacteria in such disorders as cystic fibrosis, chronic bronchitis, and chronic sinusitis.